THE COMPOSITE LIFE HISTORY OF PUCCINIA 
PODOPHYLLI SCHW. 1 
By H. H. Whets el, Professor of Plant Pathology , Cornell University; H. S. Jack- 
son, Chief in Botany , and E. B. Mains, Associate in Botany , Purdue University 
Agricultural Experiment Station 2 
The common rust, Puccinia podo - 
phylli Schw., presents certain features 
which make it of special interest to 
the student of the biology of this great 
group of plant parasites. The interest 
in this species lies primarily in the 
peculiar sequence in the seasonal 
appearance of the spore forms. This 
species is an opsis-form, possessing 
aecia and telia only, and occurs on the 
common mandrake or May-apple, 
Podophyllum peltatum L., practically 
throughout its range. 
Puccinia podophylli produces telio¬ 
spores at two different periods during 
the season; the first crop appears early 
in the spring on the sheath leaves or 
bud scales, on the stem usually at the 
base and sometimes on the sepals (PI. 1, 
A and B); the second crop appears later 
in the summer on the under side of the 
fully expanded and matured leaves 
(PI. 4, B). Between these two crops 
of teliospores the aecia, usually pre¬ 
ceded by pycnia, are developed on the 
expanding leaves (PI. 2). It is also of 
interest that telia often develop in 
association with the aecial clusters on 
the leaves and to all appearances on 
the same mycelium before the appear¬ 
ance of the second crop of teliospores, 
which obviously develop from aecial 
infection (Pis. 2, 3, and 4, A). The ex¬ 
planation of the origin of these early 
telial sori and the determination of the 
life history of this species are the objects 
of the study reported in this paper. 
HISTORY 
The only previous attempt to explain 
the life history of this species and the 
sequence of the spore forms was made 
by Olive ( 6 ). Based primarily on 
cytological evidence, he reached the 
conclusion that the first crop of telia 
and the pycnia and aecia arise from 
an intermingled growth of the mycelium 
of the gametopihytic and sporophytic 
generations which are independently 
and simultaneously perennial in the 
host plant. He conducted no culture 
work nor did he attempt to verify this 
assumption by an histological study of 
the root stalk or overwintering buds. 
The following summary of Olive’s 
work is presented in some detail, 
largely by quotation, in order to bring 
out clearly his cytological observa¬ 
tions and the conclusions he drew from 
them since it will be necessary to refer 
to these details later in this paper. 
Olive found that the mycelium in the 
lesions on the sheath leaves that bore 
the early telia was prevailingly binu- 
cleate, as one would expect. 
The preparations also show, occasionally, a few 
aecidium cups on these same sheaths * * *. I 
have not yet found spermogonia on the sections of 
these young sheaths; but their occasional occurrence 
in such situations may be expected from the fact 
that a small amount of uninucleate mycelium 
occurs, especially in the region surrounding the 
aecidial sori, there forming the meager pseudo-paren¬ 
chyma. But the rust mycelium of the sheath, in 
contradistinction to that in the young leaves, is 
undoubtedly prevailingly binucleate. Further, I 
1 Received for publication May 24, 1924—issued April, 1925. Joint contribution from the Department of 
Botany, Purdue University Agricultural Experiment Station and the Department of Plant Pathology, 
Cornell University. 
2 A report on the experiment conducted at Ithaca, N. Y., together with an interpretation of the life history 
essentially the same as that given in this paper, was presented before the Botanical Society of America at 
the Pittsburgh meeting of the American Association for the Advancement of Science in 1917 by Prof. H. H. 
Whetzel (not published). The problem had been freely discussed with me during the two previous years 
and my interest aroused. It was mutually agreed that a more detailed cultural study would be desirable 
and this work was begun at LaFayette, Ind., in 1917, having been planned in collaboration with my associate, 
Dr. E. B. Mains, who carried out the details of the cultures. It was finally decided to present the combined 
results in a joint paper, the preparation of which has been my responsibility.—H. S. Jackson. 
3 Reference is made by number (italic) to “Literature cited.” 
Journal of Agricultural Research, 
Washington, D. C. 
13949—25f-5 
Vol. XXX No. 1 
Jan. 1, 1925 
Key N. Y. (Cornell)-5 
(65) 
